A Letter from General Washington, dated yesterday, was received and read, and is in the words following, to wit:

"August 30, 1776.

"SIR: Your favour of this date is just come to hand. Circumstanced as this Army was in respect to situation, strength, &c&dot;, it was the unanimous advice of a council of General Officers to give up the Long-Island and not, by dividing our force, be unable to resist the enemy in any one point of attack. This reason, added to some others, particularly the fear of having our communication cut off from the main body, (of which there seemed to be no small probability,) and the extreme fatigue our troops were laid under in guarding such extensive lines, without proper shelter from the weather, induced the above resolution.

"It is the most intricate thing in the world, sir, to know in what manner to conduct one' s self with respect to the Militia. If you do not begin many days before they are wanted, to raise them, you cannot have them in time; if you do, they get tired and return, besides being under very little order or government whilst in service. However, if the enemy have a design of serving us at this place, as we apprehend they meant to do on Long-Island, it might not be improper to have a body in readiness to prevent or retard a landing of them on the east of Harlem River, if need be.

"In haste, and not a little fatigued, I remain, with great respect and esteem, sir, your most obedient, humble servant,

"Go&dot; WASHINGTON.

"The Hon&dot; Abraham Yates, Esq&dot;, President of the Congress of the State of New-York."

The said Letter was immediately taken into consideration, and the Committee came to the following Resolution, to wit:

Whereas, from the operations of the enemy and the intelligence received, there is strong reason to think that their Army intend to make a landing at or near King' s Bridge, in order to cut off the communication betwixt New-York Island and the Main:

Resolved, That the inhabitants of New-York Island and those parts of Westchester County which are most exposed to the depredations of the enemy, do forthwith drive their Horned Cattle, Horses, Hogs, and Sheep into the interior part of this State, and that General Washington be requested to make this order publick, and to give all possible assistance in carrying it into execution when he shall think necessary.